Air atomizing spray guns direct a stream(s) of air at a fluid stream as it exits the nozzle to atomize the fluid stream. As shown in FIG. 1, many conventional air atomizing spray guns use a needle valve assembly to regulate fluid flow. A needle valve allows for extremely accurate control of the fluid stream at the point of delivery (e.g., the needle tip). The needle valve assembly has a needle disposed in the fluid passage of a nozzle. The needle end seats in the nozzle tip effectively cutting the fluid flow. A variety of means are used to displace the needle through the fluid passage such as trigger activated spring driven pistons and air cylinder driven pistons. Some spray guns are equipped with such features as nozzle extensions and elbow joints which facilitate the spraying of difficult to reach places such as pipe interiors. Nozzle extensions are provided with extra long needles and elbow joints are provided with cam assemblies to translate the direction of the needles.
Generally, these spray guns work well, however there is a constant search for improvements particularly when spraying mixtures such as fiber-containing fluids.